Controlled room temperature synthesis of magnetic metal oxide nanoclusters within a diblock copolymer matrix

ABSTRACT

A method of room temperature synthesis of magnetic metal oxide nanoclusters within a diblock copolymer matrix includes the step of synthesizing, by ring opening metathesis polymerization technique, a diblock copolymer having a repeat unit ratio m/n, introducing, at room temperature, one or several metal containing precursors into the one block of the diblock copolymer, and processing the metal containing diblock copolymer by wet chemical technique to form nanoclusters of the metal(s) oxide within the diblock copolymer matrix. Specific reaction for synthesis of CoFe 3 O 4  and Co 3 O 4  nanoclusters within diblock copolymers, such as [NOR] m /[NORCOOH] n  and [NOR] m /[CO(bTAN)] n , respectively is used in the method of the present invention.

REFERENCE TO RELATED APPLICATIONS

The present Utility Patent Application is based on Provisional PatentApplication No. 60/340,033, filed 30 Nov. 2001, and Provisional PatentApplication No. 60/340,065, filed 30 Nov. 2001.

This invention was made with Government support and funding from NSFContract No. CTS 9875001. The Government has certain rights in thisinvention.

FIELD OF THE INVENTION

The present invention relates to nanocluster fabrication; and moreparticularly to the development of self-assembled magnetic metal oxidenanoclusters within a diblock copolymer matrix.

Further, the present invention relates to synthesis of magnetic CoFe₂O₄nanoparticles within a diblock copolymer matrix.

Still further, the present invention pertains to the development offerromagnetic Co₃O₄ nanoparticles within a diblock copolymer matrix.

Furthermore, in a more detailed concept thereof, the present inventionis directed to the room temperature synthesis of metal oxide containingnanocomposite achieved by incorporating metal(s) oxide intoself-assembled nanodomains of diblock copolymers having a predeterminedrepeat unit ratio for each block which are synthesized by the techniqueof ring opening metathesis polymerization in the presence of a catalyst.

BACKGROUND OF THE INVENTION

Nanocrystalline materials are nano composites characterized by anultrafine grain size (less than 50 nm). Nanoclusters are the subject ofcurrent interest due to their unusual optical, electronic, and magneticproperties which often differ from their bulk properties. The spatialconfinement of electronic and vibrational excitations in nanoclustersresult in a widening of the energy band gap and observation of quantumsize effects. Quantum size effects and large surface to volume ratioscan contribute to the unique properties of nanoclusters, which forexample include a phenomena that when below a critical size the magneticparticles become a single magnetic domain and are superparamagnetic.

Although nanoclusters have received attention from both theoretical andexperimental standpoints, the greatest challenge at the present time isto find out an effective synthesis procedure. The fundamental challengesin nanostructured materials include: ability to control the scale of thenanostructured system; ability to obtain the required composition withthe controlled effects, concentration gradients, etc.; understanding theinfluence of the size of building blocks in nanostructured materials, aswell as the influence of microstructure of the physical, chemical, andmechanical properties of this material; and transfer of developedtechnologies into industrial applications including the development ofthe industrial scale of synthesis methods of nanomaterials andnanostructured systems.

A number of methods of nanocluster fabrication have been developed whichinclude Radio frequency plasma torch synthesis of γ-FeNx nanoclustershave been reported by Z. Turgut, et al. of Carnegie Mellon University.In their approach, a plasma gas mixture of argon and hydrogen were usedas a sheath gas. Micron sized iron particles were injected into theplasma stream using argon as a carrier gas. Ammonia was used as anitrogenization source. By controlling the injection rate, a mixture of27 nm FeNx and 55 nm Fe powder was achieved.

Graphite encapsulated metal nanoclusters were reported to be synthesizedby D. Lynn Johnson, et al. of Northwestern University using hightemperature electric arc technique. Carbon and metals of interests wereco-evaporated by producing an electric arc between a tungsten cathodeand a graphite/metal composite anode. The encapsulation occurredin-situ. The powdered material collected consisted of GEM and bare metalnanocrystal as well as amorphous carbon particles.

PbS and CdS colloids of nanometer dimension have been reported to besynthesized by controlled precipitation of the metal sulfide in waterand acetonitrile solution (H. J. Watzke, et al., Journal of PhysicalChemistry, 91, 854, 1987). Although these colloids have shown quantumsized effects, they have a broad size distribution. Synthesis ofnanoclusters other than CdS and ZnS has thus far been substantiallyunsuccessful.

CdS nanoclusters have been synthesized within the pore structure of thezeolite (Y. Wang, et al., Journal of Physical Chemistry, 91, 257, 1987).The coordination of Cd atoms with the framework of oxygen atoms of thedouble six ring windows of zeolite leads to formation of stablenanoclusters with the structural geometry superimposed by the matrix.

Metal nanoclusters have been prepared by the solution phase thermolysisof molecular precursor compounds (J. G. Brennan, et al., ChemicalMaterials, 2, 403, 1990), such as [Cd(SePh)₂]2[Et2PCH2CH2PeT2].

Nanocluster of CdSe has been synthesized using organometallic reagentssuch as Se(TMS)₂ in inverse micellar solution (A. P. Alivisatos, et al.,Journal of Physical Chemistry, 90, 3463, 1989). Arrested precipitationin reverse miscelles gives a bare semiconductor lattice and in situmolecular modification of the cluster surface enables isolation of themolecular product with a variety of organic surface ligands.

Gold nanoclusters have been fabricated using a metal vapor depositiontechnique (J. K. Klabunde, et al., Chemical Material, 1, 481, 1989). Inthis method, gold vapor was codeposited with liquid styrene or methylmethacrylate (as vapor) at liquid nitrogen temperature.

The first successful attempt to use block copolymer to fabricate metalnanoclusters is believed to have been accomplished by Morkned, et al.(Applied Physics Letters, 64, 422, 1994). In this method, metal vaporwas deposited on the surface of a microphase separated PS-PMMA diblockcopolymer. After deposition, the film was annealed under vacuum fortwenty-four hours. The resulting nanoclusters had a narrow sizedistribution. The shape and size of the nanoclusters were additionallyfine tunable.

Recently, research at MIT (R. T. Clay, et al., Supra Molecular Science,4, 113, 1997) and at the University of Maryland, College Park havesynthesized metal nanoclusters inside the microphase separated domainsof diblock copolymer. The self-assembled nature of domain structurespermits good control over the shape and size of nanoclusters. Polymermatrix also provides kinetic hindrance to aggregation of nanoclusters oflarger particles. Nanoclusters within block copolymer show 3-D orderingand furthermore the density of nanoclusters are high enough forsynthesizing non-linear devices for commercial applications.

Metal nanoclusters of Cu, Ag, Pd, Pt, and binary metal oxidenanoclusters of Fe₂O₃ and CuO have been synthesized within microphaseseparated domains of diblock copolymers [Y. N. G. Scheong Chan, et al.,Chemical Material, 4, 1992, 24, Y. N. G. Scheong Chen, et al., Journalof American Chemical Society, 114, 1992, 7295, Y. N. G. Scheong Chen, etal., Chemical Materials, 4, 1992, 885, and B. H. Sohn, ChemicalMaterials, 9, 1997, 113]. The self-assembled nature of the micro-domainspermits control over the shape and size of the nanoclusters. Theinterfaces between the blocks of the diblock copolymers play animportant role in the nucleation and growth of clusters and induces anarrow size distribution. The polymer matrix additionally providesschematic hindrance to aggregation of nanoclusters.

Cobalt ferrite, CoFe₂O₄, is a well-known hard magnetic material withhigh cubic magneto-crystalline anisotropy, high coercivity and moderatesaturation magnetization. It would be highly desirable to provide roomtemperature synthesis of mixed metal oxide nanoclusters within a polymermatrix for obtaining diblock copolymer-CoFe₂O₄ nanocomposites with theneeded magnetic properties while only single metal incorporation withina block copolymer nanodomain has been reported thus far using similartechniques. It would also be highly desirable to have a novel way ofassociating the metal (Co and/or Fe) to the polymer in the liquid state.Moreover, the specific reaction scheme for Co₃O₄ nanocomposites, wherethe Co atoms are directly attached to the monomer during itspolymerization, is also desirable for obtaining ferromagneticnanoparticles within a diblock copolymer matrix.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodfor controlled room temperature synthesis of magnetic CoFe₂O₄nanoclusters within a diblock copolymer matrix.

It is another object of the present invention to provide a method forcontrolled room temperature synthesis of polymer Co₃O₄ nanocompositewithin a diblock copolymer matrix.

It is still an object of the present invention to provide a method forsynthesis of self-assembled magnetic CoFe₂O₄ or Co₃O₄ nanoparticles atroom temperature using a microphase separated diblock copolymer as atemplate. In this method, diblock copolymers are synthesized using ringopening metathesis polymerization with a predefined repeat unit ratiofor each block. In this manner, the self-assembly of the CoFe₂O₄ mixedmetal oxide magnetic nanoparticles, or Co₃O₄ nanocomposite takes placewithin the spherical microphase separated morphology of the diblockcopolymer which serves as the templating medium. The self-assembly ofthe magnetic metal(s) oxide within the diblock copolymer matrix isachieved at room temperature by introducing metal(s) containingprecursor(s) into one of the polymer blocks and by subsequent processingof the copolymer by wet chemical methods to substitute the chlorineatoms with oxygen.

The present invention is a method of room temperature synthesis ofmagnetic metal oxide nanoclusters within a diblock copolymer matrixwhich includes the steps of:

-   -   (a) synthesizing through a ring opening metathesis        polymerization technique, a diblock copolymer which includes a        first polymer block and a second polymer block, with both blocks        being of predetermined “length”, such that a resulting diblock        copolymer has a predetermined repeat unit ratio m/n of the first        and second polymer blocks, respectively;    -   (b) introducing at room temperature, one or more precursors,        which are salts of one or several metals, into one block of the        diblock copolymer (prior or after the formation of the diblock        copolymer), thus forming a copolymer with the metal or metals        attached to one of the polymer blocks in the diblock copolymer;        and    -   (c) processing the resulting metal(s) containing diblock        copolymer by a wet chemical technique to form single metal or        multi-metal oxide nanoclusters within the diblock copolymer        matrix.

The repeat unit ratio m/n may be changed either by increasing ordecreasing the rate of polymerization, or by increasing and decreasingthe time period the polymerization takes place.

The method of the present invention may be used for synthesis ofdifferent metal oxide nanoclusters in different diblock copolymers. Forexample, for synthesis of CoFe₂O₄ nanoclusters, the method contemplatesthe steps of:

-   -   ring opening metathesis polymerization of norbornene (NOR) and        norbornene trimethylsilane (NORCOOTMS) in presence of a        catalyst, preferably Grubb's catalyst, to form a        [NOR]_(m)/[NORCOOTMS]_(n) diblock polymer;    -   converting the [NOR]_(m)/[NORCOOTMS]_(n) diblock copolymer into        [NOR]_(m)/[NORCOOH]_(n) diblock copolymer by precipitating the        obtained in the previous step diblock polymer in a mixture of        methanol, acetic acid and water;    -   introducing FeCl₃ and CoCl₂ precursors into the diblock        copolymer, so that FeCl₃ and CoCl₂ molecules attach themselves        to the NORCOOH block;    -   forming solid films of the mixture of diblock copolymer, FeCl₃        and CoCl₂; and    -   washing the solid films with NaOH and water, thus forming        CoFe₂O₄ nanoclusters within the [NOR]_(m)/[NORCOOH]_(n) diblock        copolymer matrix.

In the step of ring opening metathesis polymerization of a diblockcopolymer, it is contemplated, that either first the step ofpolymerization of norbornene molecules is initiated by introducing acatalyst solution to the solution of norbornene (NOR) in THF (anhydroustetrahydrofuran) and the molecules of NORCOOTMS are added to thenorbornene polymer. Alternatively, the polymer molecule of NORCOOTMS isformed first by adding the Grubb's catalyst solution to the solution ofNORCOOTMS in THF, and the norbornene (NOR) molecules are added to theNORCOOTMS afterwards. The major requirement for the stage ofpolymerization of diblock copolymer is to permit sufficient time forpolymerization of both polymolecules of the diblock copolymer in orderto achieve a predetermined repeat unit ratio m/n. Although different m/nratios are contemplated in the subject method it is preferred thatm/n=400:50.

The introduction of the Fe and Co salts into the diblock copolymer takesplace in liquid phase. This facilitates the uniform distribution ofmetal containing nanoclusters in the diblock copolymer matrix as opposedto solid phase doping techniques. The method of the present inventionpermits the attainment of a highly uniform doping of the nanoclustersystem. Such a uniformity of nanoclusters incorporated into the diblockcopolymer matrix is important for the application of the nanostructuresas data storage where the isolation of nanoclusters from each other, aswell as the uniform separation between adjacent nanoclusters within thediblock copolymer matrix is of essence for proper operation of suchinformation storage.

After complete polymerization of the diblock copolymer is accomplished(when the repeat unit ratio m/n is achieved), the process ofpolymerization is terminated, preferably by adding an unsaturated etherwhich cleaves the molecules of catalyst from the polymer chain thusdeactivating the polymerization.

The method of the present invention further contemplates a roomtemperature synthesis of Co₃O₄ nanoclusters within a diblock copolymermatrix, which includes the steps of:

-   -   synthesis of Co(bTAN) by mixing a solution of CoCl₂ in        tetrahydrofuran and a solution of Li₂(bTAN) which is        lithium-trans-2,3-bis (tert-butylamidomethyl) norborn-5-ene in        ether;    -   ring opening metathesis polymerization of norbornene (NOR) and        the Co(bTAN) in presence of a catalyst to form        [NOR]_(m)/[Co(bTAN)]_(n) diblock copolymer;    -   forming solid films of said [NOR]_(m)/[Co(bTAN)]_(n) diblock        copolymer; and    -   washing the solid films with hydrogen peroxide H₂O₂, thus        forming Co₃O₄ nanoclusters within the [NOR]_(m)/[Co(bTAN)]_(n)        diblock copolymer matrix.

Prior to introducing of CoCl₂ into the Li₂(bTAN), the CoCl₃ is dissolvedin tetrahydrofuran, so that attachment of metal containing molecules tothe Li₂(bTAN) is achieved directly in the liquid phase thus greatlyimproving the uniformity of distribution of metal containingnanoclusters within the diblock copolymer matrix.

The polymerization of the [NOR]_(m)/[Co(bTAN)]_(n) diblock copolymer isinitiated by adding the Grubb's catalyst to the solution of thenorbornene (NOR) in benzene. Further, the C(bTAN) is added to the NORpolymer solution after approximately 15 minutes from the introduction ofthe Grubb's catalyst to form a resultant diblock copolymer[NOR]_(m)/[Co(bTAN)]_(n).

The resultant diblock copolymer is further precipitated in pentane andthe precipitated diblock copolymer is dried and dissolved in benzene.

The solution of the precipitated diblock copolymer in benzene is furtherstatically cast to form solid films of the diblock copolymer containingatoms of cobalt over a period of approximately 240 hours, and the solidfilms are further washed with hydrogen peroxide for a period ofapproximately 24 hours to form Co₃O₄ nanoparticles within[NOR]_(m)/[Co(bTAN)]_(n) diblock copolymer matrix.

These and other novel features and advantages of this invention will befully understood from the following detailed description of theaccompanying Drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of thepoly(norbornene)-poly(norbornene-dicarboxylic acid) diblock copolymer;

FIG. 2 shows the synthesis of the [NOR]_(m)/[NORCOOH]_(n) diblockcopolymer;

FIG. 3 shows an alternative technique for diblock copolymer synthesis;

FIG. 4 presents schematically the room temperature wet chemicalsynthesis scheme for CoFe₂O₄ nanostructures;

FIGS. 5A and 5B present results of the FTIR (Fourier Transform InfraredSpectroscopy) study of the nanocomposites in the copolymer solution andin the solid copolymer, respectively;

FIG. 6 is a representation of the image of the morphology of the diblockcopolymer-CoFe₂O₄ nanocomposite obtained with a transmission electronmicroscope (TEM);

FIG. 7 is a diagram of intensity vs. angle obtained by wide angle X-rayof the nanoclusters within the diblock copolymer, confirming the CoFe₂O₄nanocomposition formation;

FIG. 8 is a representation of a structure of created CoFe₂O₄;

FIGS. 9–10 are Mossbauer Spectra of polymer-CoFe₂O₄ nanocomposite takenat 300° K and 4° K, respectively;

FIGS. 11–14 are diagrams representing magnetic properties ofpolymer-CoFe₂O₄ nanocomposite for diblock copolymers with differentrepeat unit ratios;

FIG. 15 shows schematically the process of synthesis ofnorbornene-cobalt monomer;

FIG. 16 shows the process of [NOR]_(m)/[Co(bTAN)]_(n) synthesis;

FIG. 17 shows the process of Co₃O₄ nanocluster formation;

FIG. 18 is a diagram representing magnetic properties of synthesizedCo₃O₄ nanostructures at room temperature;

FIG. 19 is the image of cobalt oxide nanoclusters obtained withtransmission electron microscope (TEM); and,

FIG. 20 is a diagram representing a FTIR (Fourier transform infraredspectroscopy) spectra for the sample of the created Co₃O₄ nanocomposite.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a process of controlled room temperaturesynthesis of self-assembled magnetic metal(s) oxide nanoparticles withinthe diblock copolymer matrix. The method of the present invention uses amicrophase separated diblock copolymer as a template for the formationof nanostructures, such as a single metal oxide or a multi-metal oxide.For both types of resulting product (single or multi-metal oxidenanostructures), metal(s) atoms may either be introduced to one block ofa diblock copolymer as a salt when the polymer is dissolved, or to onemonomer prior to the polymer synthesis. However, despite the differencesin these two approaches, the overall method of room temperaturesynthesis of magnetic metal oxide nanoclusters within a diblockcopolymer matrix of the present invention includes the following steps:

-   -   synthesizing by a ring opening metathesis polymerization        technique, a diblock copolymer which includes a first polymer        block and a second polymer block having a predetermined repeat        unit ratio m/n of the first and second polymer blocks,        respectively,    -   introducing at room temperature in a liquid phase, metal or        metals into one of the blocks of the diblock copolymer (prior or        after polymerization of the diblock copolymer), and    -   processing the metal (or metals) containing diblock copolymer by        wet chemical technique to form nanoclusters of the metal (or        metals) oxide within the diblock copolymer matrix.

The following description of the method of the present invention will befurther presented with regard to synthesis of magnetic CoFe₂O₄nanoclusters and Co₃O₄ nanoclusters, although it will be readilyapparent to a person skilled in the art that the principles andteachings of the method of the present invention are applicable to thetemplating of nanostructures of many other metals and semiconductorswithin diblock copolymer nanodomains for synthesis of metal(s) oxidemagnetic nanoclusters within diblock copolymer matrices.

As such, for the synthesis of CoFe₂O₄ nanoclusters, diblock copolymers10 shown in FIG. 1 consisting of a block of poly-norbornene (NOR) 12 andpoly(norbornene-dicarboxcylic acid), also referred to herein as NORCOOH,block 14 was synthesized using ring opening metathesis polymerizationpresented in further detail in following paragraphs with regard to FIGS.2 and 3, with a repeat unit ratio m/n for each block. The self-assemblyof the CoFe₂O₄ mixed metal oxide magnetic nanoparticles takes placewithin the spherical microphase separated morphology of the diblockcopolymer 10 which serves as the templating medium. The self-assembly ofthe magnetic oxide within the diblock copolymer matrix is achieved atroom temperature in the liquid phase by introducing FeCl₃ and CoCl₂precursors into the second polymer block (NORCOOH) 14 and by thesubsequent processing of the copolymer by wet chemical methods tosubstitute the chlorine atoms with oxygen.

The diblock copolymer [NOR]_(m)/[NORCOOH]_(n) 10 is synthesized by twotechniques, shown respectively in FIGS. 2 and 3, however, norbornene(NOR) and norbornene trimethylsilane (NORCOOTMS) were used as theinitial materials in both techniques.

Referring to FIG. 2, showing the first technique of the diblockcopolymer synthesis, the diblock copolymer synthesis begins withpreparation of 4% solution of norbornene (NOR) 16 in anhydroustetrahydrofuran (THF) 18 by dissolving one gram NOR (5.5×10⁻³ mol 400equivalent) in 25 ml THF. The polymerization of the norbornene (NOR) wasinitiated by adding 0.75 ml (13.75×10⁻⁶ mol, 1/400 equivalent) of Grubbscatalyst solution 20. The Grubb's catalyst(BIS(tricyclohexylphosphin)benzylidine ruthenium(IV)dichloride) is acatalyst purchased from Sterm Chemicals the stock solution (30 mg/ml) ofwhich was prepared by dissolving the catalyst in THF and CH₂Cl₂. TheGrubb's catalyst has high tolerance towards impurities and hence enablesthe use of commercially available norbornene without furtherpurification. Thus, as can be seen in FIG. 2, the initial norbornene 16dissolved in THF 18 is polymerized by means of Grubb's catalyst reactionwith the norbornene to form a polymolecule 22 containing n open ringnorbornene molecules. After approximately an hour since initiating ofthe polymerization of norbornene, NORCOOTMS solution 24(2-NORBORNENE-5,6,-dicarboxylic acid BIS trimethylsilyl ether which had44×10⁻³ mol, 50 equivalent) is added to the living polymer solution 22to form a molecule 26 including N polymolecules 22 and M polymolecules26, which, as can be seen in FIG. 2, included the molecule of theGrubb's catalyst.

The reaction of polymerization was terminated after 24 hours by additionof unsaturated ether 28 which cleaves the catalyst from the chainmolecule 26 and leaves the resultant [NOR]_(m)/[NORCOOTMS]_(n) diblock30. The diblock 30 is further precipitated in a mixture of methanol,acetic acid and water (4:25:50) to result in [NOR]_(m)/[NORCOOH]_(n)diblock copolymer 32 which is dried under vacuum before the furtherprocessing.

Referring to FIG. 3, in the synthesis of nanoclusters in the diblockcopolymer, the sequence of monomer addition has been-changed. In thealternative embodiment, norbornene dicarboxylic acid trimethylsilylester is added as the first block to control the polydispersity. Inorder to control the polydispersity of the block copolymer, the bulkier2-norbornene-5,6,-discarboxylic acid bis trimethylsilyl ester(NORCOOTMS) 24 is the first monomer to be polymerized.

The steric interference between the NORCOOTMS monomers and inhibition ofGrubb's catalyst controls the rate of propagation of NORCOOTMS. Thisresults in a controlled polymerization, with a narrow polydispersityindex. When norbornene, which by itself cannot be homopolymerized with anarrow polydispersity index, is added to the propagating species, theresulting block copolymers has a polydispersity index less than 1.26.This study has shown that the polydispersity index can be controlled byselecting a monomer with proper functionality as the starting block ofthe block copolymer to control rate of propagation as an alternative ofusing additives to change the reactivity of the catalyst. Selection ofthe proper functionality depends on the polarity and bulkiness of thefunctional group to interact with the catalyst.

Referring to FIG. 3, showing the alternative process of creating the[NOR]_(m)/[NORCOOH]_(n) diblock copolymer, the process begins with theinitial NORCOOTMS 24, the polymerization of which starts with addingGrubb's catalyst 20 to form a chain 34 containing n molecules ofNORCOOTMS with the catalyst attached to the chain. Norbornene 16 isfurther added to the chain 34 and the process of copolymerizationcontinues for a number of hours to allow for complete polymerization andformation of the chain 36 of m norbornene molecules and n NORCOOTMSmolecules with the Grubb's catalyst attached to such diblock chain 36.The reaction of polymerization further is terminated by addingunsaturated ether which cleaves the molecule of catalyst from the chain36, thus leaving the resultant molecule [NOR]_(m)/[NORCOOTMS]_(n), whichis further converted to [NOR]_(m)/[NORCOOH]_(n) by precipitating thepolymer solution 30 in a mixture of methanol, acetic acid and water,similar to the process shown in FIG. 2. The polymers are dried undervacuum before static film casting.

Further, the [NOR]_(m)/[NORCOOH]_(n) diblock copolymer created duringthe stage of polymer synthesis, is dissolved in THF, and, as shown inFIG. 4, FeCl₃ and CoCl₂ precursors 38 were mixed with the polymersolution in the following relationship: polymer:FeCl₃:CoCl₂=1:25.0:12.5mole. Due to the high affinity of the Fe and Co towards the COOH groupof the diblock copolymers 32, FeCl₃ and CoCl₂ are attached to theNORCOOH block of the diblock copolymer. From the solution 40, a polymerfilm may be static cast into a Teflon cup or it may be spin cast onto asubstrate. Solid films 42 have been formed by static casting over aperiod of three days. The films 42 are then washed with NaOH and water.The molecules of FeCl₃ and CoCl₂ microphase separated within the film42, reacts with NaOH and water within the NORCOOH nanoreactors and as aresult, CoFe₂O₄ nanoclusters 44 are formed within the self-assembledNORCOOH nanospheres 46 of the diblock copolymer matrix 48.

Static cast films are produced by slowly evaporating the solvent overthree days, and then placed under vacuum to remove any residual solvent.Films are analyzed with X Fourier Transform Infrared Spectroscopy (FTIR)to verify the association of the metals to the carboxylic groups on thesecond block NORCOOH block 14 of the diblock copolymer 10, as shown inFIGS. 5A and 5B. The spectra, taken in the range of 4,000 to 800 cm⁻¹ ona Nicolet Fourier transform spectrometer show that the metals areselectively attached to COOH block (FIG. 5A). Partial metaldisassociation from COOH block before oxidation, and completedisassociation of metal from the diblock copolymer after oxide formationis observed (FIG. 5B). FTIR presented in FIGS. 5A and 5B, verified thatthe metals are associated to the second block (NORCOOH) of the diblockcopolymer 10 and not dispersed randomly as filler in the matrix.

A SQUID magnetrometer was employed to study the magnetic-properties ofthe [NOR]_(m)/[NORCOOH]_(m)—CoFe₂O₄ nanocomposites at an applied fieldup to 50KOE and at a temperature range from 300K to 4K. Morphology andmicrostructure of the nanocomposite films were determined using TEM(Transmission Electron Microscope) and ⁵⁷Fe Mossbauer spectroscopy.

The repeat unit ratio m/n of the NOR block 12 and NORCOOH block 14 ofthe diblock copolymer 10 was varied to form diblock copolymers with thefollowing ratios of m/n: 400/50, 400/150, 400/200, and 400/250. Forexample, for m/n=400/50, the CoFe₂O₄ nanoclusters exhibited a uniformlydispersed spherical morphology within the polymer matrix with an averageradius of 4.8±1.4 nm. The magnetic properties of the polymer films weredominated by surface effects. At room temperature, the nanocompositefilms were found to be superparamagnetic and had a magnetization of 1.03emu/g (equivalent to 18.04 emu/g of CoFe₂O₄). At 5K, the nanocompositefilms become ferromagnetic with coercitivity=5.3KOE, equivalentremanence=11.93 emu/g and equivalent maximum magnetization=57.1 emu/g.The reduction in magnetization is due to the presence of a magneticallydisordered surface layer of sequence approximately 5.5 angstrom.

Referring to FIG. 6, the morphology of the [NOR]₄₀₀/[NORCOOH]₅₀—CoFe₂O₄nanocomposites was studied using a Hitachi H-600 transmission electronmicroscope (TEM) operated at 100 KEV. Block copolymers were embedded inepoxy and ultra-thin (100 nm) samples for TEM observation were preparedwith a diamond knife using a LKB Ultratome III model 8800. The sampleswere placed on a carbon coated nylon grid to reduce beam damage. Theimage obtained by the TEM technology, as shown in FIG. 6, indicates thatthe clusters have a relatively narrow size distribution, and areuniformly distributed within the polymer matrix. It is also seen fromthe image that the CoFe₂O₄ nanoclusters are almost spherical in shapeand have an average radius of 4.8±1.4 nm.

The films of the [NOR]₄₀₀/[NORORCOOH]₅₀—CoFe₂O₄ were also analyzed withX-ray photo-electron spectroscopy to confirm CoFe₂O₄ formation. A PerkinElmer 5800 XPS-Auger spectrometer was used to collect the spectrapresented in FIG. 7. High resolution scan of the specific peaks ofinterest were obtained and the formation of CoFe₂O₄ was confirmed.

The Mossbauer spectra of the diblock copolymer films were obtained usinga conventional constant acceleration Ranger Electronics CorporationMossbauer spectrometer driven by a triangular waveform. The source was25 mCi⁵⁷Co in a Rh matrix maintained at room temperature. Thespectrometer was calibrated with an iron foil. Spectral fits wereperformed assuming Lorentzian absorption line shapes. Sampletemperatures were varied between 4.2 K and 300 K using a Superveritemp™cryogenic dewar (Janis Research Corporation) configured with aLakeshore, Inc. temperature controller. The magnetic structure of theCoFe₂O₄ nanoclusters was analyzed using Mossbauer spectroscopy. BulkCoFe₂O₄ exhibits the inverse spinel structure shown in FIG. 8, with Co²⁺mostly at octahedral B sites and Fe³⁺ almost equally distributed amongtetrahedral A and octahedral B sites. Ferromagnetism in CoFe₂O₄ is dueto the intra-lattice exchange interaction (J_(AB) which is much greaterthan the inter-lattice interaction (J_(BB)). The magnetic moment of ionson B sites is aligned parallel to the direction of the net magnetizationand anti-parallel to that of a site.

As shown in FIGS. 9 and 10, Mossbauer investigation of the CoFe₂O₄diblock copolymer films were performed at 300 and 4.2 K for differentrepeat unit ratio m/n of the diblock copolymer. The room temperaturespectra, shown in FIG. 9 are complex. They exhibit a quadrupolarcomponent at the center of the spectrum and a magnetically splitcomponent spread across the spectrum. At room temperature, the quadruplesplitting dominates the magnetic splitting and hence the sample issuperparamagnetic. The intensity of the quadruple splitting decreaseswith the temperature. At 4.2 K, as shown in FIG. 10, only the magneticsplitting is present and the CoFe₂O₄ block copolymer is completelymagnetic.

The room temperature and the 4.2° K spectra were analyzed further toinvestigate the magnetic hyperfine structure of CoFe₂O₄ nanoclusters.The slight asymmetry in the intensity of the absorption lines of thequadrupole doublet indicates the presence of two poorly resolved ironsubsites. The presence of two iron subsites is further suggested by thefine structure observed in the magnetic spectral lines. These sites wereattributed to iron ions at tetrahedral A and octahedral B sites of thespinel structure shown in FIG. 8. The experimental data shown in FIG. 9were fit to the superposition of two doublets and two magnetic sextets,and the data shown in FIG. 10 were fit to the superposition of twomagnetic sextets. Table 1 presents the Mossbauer parameters obtainedfrom least square fits of the spectra. Smaller isomer shifts andhyperfine fields are associated with tetrahedral sites, while largerisomer shifts and hyperfine fields are characteristic of octahedralsites B.

TABLE 1 MOSSBAUER PARAMETERS FOR DIBLOCK COPOLYMER- COFE₂O₄ Isomershift* T(K) (mm/sec) E_(Q) (mm/sec) H_(hf) Fe(A)/Fe(B) 300 0.27 0.72 —0.59 0.42 0.67 — 0.27 — 440 0.68 0.41 — 447 4.2 0.39 — 501 0.73 0.53 —526 *Isomer shifts are relative to metallic Fe at room temperature

The observation of a quadrupole splitting in the paramagnetic componentis indicative of ligand coordination distortion away from perfecttetrahedral or octhedral symmetry, E_(Q)(A)=0.72 mm/sec andE_(Q)(B)=0.67 mm/sec. The absence of an observable quadrupole splittingperturbation on the magnetic spectra indicates that the distortion isnot along the same crystallographic axis relative to the direction ofmagnetization in various particles. In such a case, the presence ofdistortion would only contribute to line broadening of the magneticspectra. This is expected in the case of small particles where largestrains at the particle/support interface are known to produce severelattice distortion. The spectral features observed at 4.2° K areconsistent with those previously reported for CoFe₂O₄ particles by otherMossbauer investigations.

Bulk cobalt ferrite is known to exhibit a partially inverse spinelhaving the formula (Co_(x)Fe_(1−x)[CO_(1−x)Fe_(1+x)]O₄), where theparenthesis indicate tetrahedral A sites and the brackets indicateoctahedral B sites. The degree of inversion measured by the ratio ofiron ions in A to B crystallographic sites has been shown to besensitive to heat treatment of the sample. It has been reported thatFe(A)/Fe(B)=0.61 for quenched samples and Fe(A)/Fe(B)=0.87 for slowlycooled samples.

In Mossbauer spectroscopy the ratio of iron ions in A and B subsites isestimated from the ratio of the absorption areas under the A and Bsubcomponents of the spectrum assuming that the recoil-free fraction foriron nuclei in tetrahedral and octahedral site symmetries is the same.For the created sample, the ratio of iron ions in A and B subsitesobserved at room temperature, FIG. 9 is equal to 0.59 for thesuperparamagnetic component and 0.68 for the magnetic component. Thisdifference may indicate a variation in the degree of inversion betweensmaller and larger particles in the distribution. However, sincerelatively large errors are usually associated with estimates ofMossbauer absorption spectral areas of poorly resolved sites one maysimply state the weighted average of these values Fe(A)/Fe(B)=0.64, asbeing characteristic of the entire sample. At 4.2° K an even largervalue of the ratio Fe(A)/Fe(B)=0.75 is obtained. However, the linebroadening observed in the magnetic spectra due to the presence of adistribution of magnetic hyperfine fields, combined with poorer spectralstatistics make the 4.2° K value less reliable. Nevertheless, all ratioestimates fall within the range of values observed for bulk orsmall-particle cobalt ferrite samples. The 4.2° K values of the internalmagnetic hyperfine fields observed, H_(hf)(A)=501 kOe and H_(hf)(B)=526kOe (Table 1) are consistent with those previously reported for COFE₂O₄magnetic fluids containing 5 nm cobalt ferrite particles.

The magnetic properties of the block copolymer samples were measuredusing a Quantum Design MPMS SQUID magnetometer. Experimentation wascarried out between 5° K and 300° K and in fields up to 50 kOe.

The magnetic properties (magnetization vs. applied magnetic field atroom temperature, 77° K and 5° K) of the CoFe₂O₄ polymer nanocompositefor m/n=400/50, 400/150, 400/200, and 400/250 are shown in FIGS. 11–14and in Table 2.

TABLE 2 Coercivity (H_(C)), remanence (σ_(T)), maximum magnetization(σ_(max)), equivalent magnetization σ_(eq) and remanence σ_(T) ^(eq) ofthe diblock copolymer-CoFe₂O₄ nanocomposite at various temperatures.T(K) H_(c)(kOe) σ_(T)(emu/g) σ_(T) ^(eq)(emu/g) σ_(max)(emu/g)σ_(eq)(emu/g) 300 0 0 0 1.03 18.04 77 0.1 3.4 · 10⁻² 0.6 2.12 37.19 55.3 0.68 11.3 3.25 57.1

The measured magnetization was divided by the total mass of the filmused.

As shown, at room temperature, the magnetization curve exhibits nohysteresis, and the nanocoposite films are perfectly superparamagnetic.Both the remanence and coercivity are zero at 300° K. The maximummagnetization σ_(max) is 1.03 emu/g at an applied field of 50 kOe.σ_(max)=1.03 emu/g corresponds to 18.04 emu/g of CoFe₂O₄ since thenanocoposite contains 5.7% of COFE₂O₄ by weight.

At 77° K, the nanocomposite films exhibit a very small remanence(σ_(T)=3.4·10⁻² emu/g) and coercivity (H_(C)=100 Oe). The maximummagnetization, σ_(max) at this temperature is 2.12 emu/g and correspondsto 37.19 emu/g of CoFe₂O₄.

At 5° K, complete blocking of spin reversal occurs and the nanocompositefilms become ferri-magnetic. At this temperature the coercivity H_(C) is5.3 kOe and the remanence σ_(T) is 0.68 emu/g, which is equivalent to11.93 emu/g of CoFe₂O₄. The maximum magnetization (σ_(max)) at thistemperature is 3.25 emu/g corresponding to 57.1 emu/g of CoFe₂O₄.

The data of Table 2 shows that although the coercivity H_(C) becomesequal to that of bulk COFE₂O₄ (5.3 kOe at 5° K), both the remanence(σ_(T)) and maximum magnetization (σ_(max)) is lower than that of thebulk oxide (67 emu/g and 80.8 emu/g, respectively). The reduction inmaximum magnetization is a manifestation of a surface effect whichresults in a core of aligned spins surrounded by a magneticallydisordered shell under the applied magnetic field. The surface spinshave multiple configurations for any orientation of the coremagnetization and do not generally contribute to the magnetization.

There are several reasons to expect surface spin disorder in ferritenanoparticles. The superexchange interaction between magnetic cations isantiferromagnetic. Ferrimagnetic order arises because theintersublattice exchange (J_(AB)) is stronger than the intrasublattice(J_(BB)) exchange. Variations in coordination of surface cations resultin a distribution of net exchange fields, both positive and negativewith respect to a cation sublattice. Since the interaction is mediatedby an intervening oxygen ion, exchange bonds are broken if an oxygen ionis missing from the surface. If organic molecules are bonded to thesurface, the electronics involved can no longer participate in thesuperexchange. Both types of broken exchange bonds further reduce theeffective coordination of the surface cations. The superexchange is alsosensitive to bond angles and lengths which would likely be modified nearthe surface.

In an ideal case, the ratio between the volume of the magneticallyactive core V_(m) and the total volume of the particle (V) is equal tothe ratio of the maximum magnetization σ_(max) (T,H) of the nanoparticleand the magnetization of the bulk material at the same temperature andmagnetic field, σ_(bulk) (T,H): $\begin{matrix}{\frac{V_{m}}{V} = \frac{\sigma_{\max}\left( {T,H} \right)}{\sigma_{bulk}\left( {T,H} \right)}} & (1)\end{matrix}$The thickness of the magnetically disordered shell at 5° K is estimatedto be 5.5 Å from Equation 1. This value is in reasonable agreement withthe reported values of small ferrite particles.

Diblock copolymers of (NOR)_(m)/(NORCOOH)_(n) were synthesized with m/nratios of 400/50, 400/150, 400/200, and 400/250. Gel permeationChromatography (GPC) confirmed that the molecular mass distribution ofthe synthesized polymer with m/n=400/50 was unimodal and was relativelynarrow as determined by the measured Polydispersity Index (PDI) of 1.15.The method of the present invention is a metal oxide templating method,which is markedly unique in that the metal salt is introduced while thepolymer is in solution before any microphase separation of the twoblocks can occur. This is a novel choice of solvents and metal materialsin order that they may be dissolved in a common solvent. The advantageswhich the disclosed templating process presents, are a rapid diffusionand attachment of the metal to the polymer since both are in the liquidstate and resultant self-assembled nanostructures at room temperaturethrough wet chemical methods. Thus, this makes a more attractive processto integrate into the fabrication of novel magnetic devices withoutrequiring additional thermal cycling steps.

The principles of the method of the present invention were also used forcontrolled room temperature synthesis of Co₃O₄, in the specific reactionscheme where the Co atom is directly attached to the monomer duringpolymerization prior to creation of the diblock copolymer. The method ofsynthesis of Co₃O₄ nanoclusters within a diblock copolymer is dividedinto stages of:

-   -   (a) synthesis of norbornene-cobalt monomer, shown in FIG. 16,    -   (b) polymer synthesis, shown in FIG. 16, and    -   (c) nanocluster formation, shown in FIG. 17.

In the stage of the monomer synthesis, shown in FIG. 15, cobalt chloride(CoCl₂) (0.47 g, 3.6 mmol) which is commercially available from Aldrich,was dissolved in 50 ml of tetrahydrofuran (THF). Li₂(bTAN)(lithium-trans-2,3-bis(tert-butylamidomethyl) norbornen-5-ene) wasprepared and 1 g (3.6 mmol) of Li₂(bTAN) 52 was dissolved in ether andthen added to CoCl₂ 50 dissolved in THF at −40° C. The mixture turned todark brown as the mixture was stirred and warmed at room temperature.After two hours, the volatile components were removed under vacuum, andthe residual was extracted with 50 ml of pentane. The solution wasextracted under vacuum and a light blue oil like Co(bTAN)(cobalt(trans-2,3-bis(TRT-butylamidomethyl) norborn-5-ene)) 54 wasobtained.

In the polymer synthesis stage, shown in FIG. 16, NOR-Co(bTAN) diblockcopolymers were synthesized by ring opening methesis polymerization ofnorbornene (NOR) 56 and Co(bTAN) 54. A 4% solution of norbornene wasprepared by disposing 0.25 g NOR 56 (2.65-3 mol, 500 equivalent) in 6 mlbenzene. The polymerization of NOR chains was initiated by adding 2.6 mg(5.3-6 mol, 1/500 equivalent) of Grubb's catalyst 58 (or adequatequantity of Schrock's catalyst) to form a chain of NOR molecules 60 withattached catalyst. Then, 5.45-2 g of Co(bTAN) 54 (21.4-3 mol, 40equivalent) was added to the living polymer solution 60 after 15 minutessince the initiation of the NOR chain polymerization to form a molecule62. The polymerization was terminated after 1 hour by adding anunsaturated ether which cleaved the molecule catalyst from the chain 62.The resultant [NOR]₅₀₀/[Co(bTAN)]₄₀ block 64 was precipitated in pentaneinside the glove box and was dried under vacuum before static filmcasting.

Further, as shown in FIG. 17, the nanocluster formation was initiatedwith preparation of 1% polymer solution 66 by dissolving the resultantdiblock copolymer 64 in benzene. Solid films 68 were formed by staticcasting the polymer solution 66 over a period of approximately ten days.The polymer film 68 with the separated microphases 70 was washed withhydrogen peroxide (H₂O₂) 72 for 24-hours. As a result, cobalt atoms weredisassociated from the polymer backbone and Co₃O₄ (cobalt oxide)nanoparticles 74 were formed.

Magnetic properties of the created nanoclusters distributed within thediblock copolymer matrix are presented in FIG. 18, showing the diagramof moment (emu/g) vs. field applied to the sample. The TEM study ofcobalt excited nanoclusters show that the polymer-Co₃O₄ nanocompositeconsists of 15 nm diameter Co₃O₄ nanoparticles embedded in a polymermatrix, as shown in FIG. 19. The nanoparticles are magnetically isolatedand the distance between the particles is approximately 15 nm. Takingthese two parameters into account, the particle density was calculatedto be 110 9/sm². Due to the ferromagnetic nature of the nanoparticles,one bit of information may be stored into each particle. As a result,ultra high density magnetic recording media with the capacity of 110gb/sm² may be fabricated using this nanocomposite. In addition to this,like traditional magnetic recording media, the metals are attached tothe polymer during synthesis and the magnetic ordering occurs duringfilm formation. These advantages will significantly reduce the number ofsteps required for fabrication of such magnetic recording media.

FTIR spectra was obtained, shown in FIG. 20. The study shows that beforeH₂O₂ wash, no amine peak is shown, indicating that cobalt atom isattached to the polymer. After H₂O₂ wash, free amine peak is observed at3400 nm indicating that Co atom is cleaved from the polymer.Additionally, the new peak at 1725 nm indicates formation of magneticcobalt oxide.

The created nanocluster of Co₃O₄ is optically transparent. Thisoptically transparent magnetic film can also be used as an invisiblemagnetic water mark in security papers. Due to the transparent thinflexibility of the material, a thin invisible pattern can be depositedon security papers. The small regions of the nanoclusters would give thewater mark a particular magnetic signature which would amount to storedinformation.

Thus, by the method of the present invention, CoFe₃O₄ nanoclusterswithin [NOR]_(m)/[NORCOOH]_(n) diblock copolymer and Co₃O₄ nanoclusterswithin [NOR]_(m)/[Co(bTAN)]_(n) diblock copolymer have been synthesizedas separated domains within diblock copolymer matrix. The self-assemblednature of domain structure permits control over the shape and size ofthe nanoclusters. Polymer matrix also provides kinetic hindrance toaggregation of nanoclusters in larger particles. Nanoclusters withinblock copolymer show 3-D ordering and the density of nanoclusters arehigh enough for synthesizing non-linear devices for commercialapplication.

Self-assembled CoFe₃O₄ and Co₃O₄ nanoclusters were successfullysynthesized at room temperature within the liquid phase by using themicro-phase separation property of diblock copolymers. The FTIR studyverified that the metal existed within the micro-phase separateddomains. The room temperature templating method of the present inventionfor self-assembly is an important step towards using the nanocompositesembedded within the diblock copolymer matrices for use in an increasingnumber of high technology applications.

Although this invention has been described in connection with specificforms and embodiments thereof, it will be appreciated that variousmodifications other than those discussed above may be resorted towithout departing from the spirit or scope of the invention. Forexample, equivalent elements may be substituted for those specificallyshown and described, certain features may be used independently of otherfeatures, and in certain cases, particular locations of elements may bereversed or interposed, all without departing from the spirit or scopeof the invention as defined in the appended claims.

1. A method of room temperature synthesis of magnetic metal oxidenanoclusters within a matrix of a diblock copolymer, comprising thesteps of: a. synthesizing, by a ring opening metathesis polymerizationtechnique, said diblock copolymer including a first polymer block and asecond polymer block having a predetermined repeat unit ratio m/n ofsaid first and second polymer blocks wherein said predetermined repeatunit ratio m/n is selected from the group consisting of m having a valueof 400 and n within the approximate range 50–250, the diblock copolymerbeing [NOR]_(m)/[NORCOOH]_(n) and said first polymer block beingnorbornene (NOR) and said second polymer block beingnorbornene-dicarboxylic acid (NORCOOH); b. introducing, at roomtemperature, FeCl₃ and CoCl₂ as precursors into said diblock copolymerto attach FeCl₃ and CoCl₂ molecules to said second polymer block(NORCOOH) of said [NOR]_(m)/[NORCOOH]_(n) diblock copolymer, therebyforming in a liquid phase the diblock copolymer containing said at leastone metal; and, c. processing said diblock copolymer by substitutingchlorine atoms of said FeCl₃ and CoCl₂ precursors with oxygen atoms toform a plurality of mixed metal oxide CoFe₂O₄ nanoclusters within said[NOR]_(m)/[NORCOOH]_(n) diblock copolymer, wherein said precursors areintroduced prior to a microphase separation of the polymer blocks. 2.The method of claim 1 wherein the step of synthesizing includes the stepof synthesizing said diblock copolymer [NOR]_(m)/[NORCOOH]_(n) by saidring opening metathesis polymerization of norbornene (NOR) andnorbornene trimethylsilane (NORCOOTMS) in presence of a Bis(tricyclohexylphosphine) benzylidine ruthenium (IV) diochloridecatalyst, resulting in the formation of a [NOR]_(m)/[NORCOOTMS]_(n)diblock copolymer solution; and, precipitating said[NOR]_(m)/[NORCOOTMS]_(n) diblock polymer solution in a mixture ofmethanol, acetic acid and water to convert said[NOR]_(m)/[NORCOOTMS]_(n) diblock polymer into said[NOR]_(m)/[NORCOOH]_(n) diblock copolymer.
 3. The method of claim 2,wherein step (a) includes the step of dissolving 1 g of norbornene (NOR)in 25 ml of anhydrous tetrahydrofuran (THF) to form a 4 gram-% solutionof norbornene (NOR) in THF prior to synthesizing said diblock copolymer.4. The method of claim 3, wherein the step of synthesizing includes thestep of initiating polymerization of said polymer block of norbornene insaid 4 gram-% solution of norbornene (NOR) in THF by adding 0.75 ml ofsaid Bis (tricyclohexylphosphine) benzylidine ruthenium (IV) dichloridecatalyst solution to said solution of norbornene (NOR) in THF.
 5. Themethod of claim 4, wherein the step of synthesizing includes the step ofadding a solution of said norbornene trimethylsilane (NORCOOTMS) to saidsolution of norbornene (NOR) in THF a predetermined time period afterinitiating the polymerization of said first polymer block of norbornene.6. The method of claim 5, wherein said predetermined time period isapproximately 1 hour.
 7. The method of claim 2, wherein the step ofsynthesizing includes the steps of: initiating synthesis of said[NOR]_(m)/[NORCOOTMS]_(n) diblock polymer solution by polymerization ofsaid polymer block NORCOOTMS by adding said catalyst solution to saidNORCOOTM; and, adding norbornene to said NORCOOTMS polymer block apredetermined time period after the initiating the polymerization ofsaid NORCOOTM polymer block.
 8. The method of claim 5, wherein the stepof synthesizing includes the step of: terminating said synthesis of[NOR]_(m)/[NORCOOTMS]_(n) approximately 24 hours after adding saidsolution of said norbornene trimethylsilane (NORCOOTMS) to said solutionof norbornene (NOR) in THF prior to said step of precipitating said[NOR]_(m)/[NORCOOTMS]_(n) diblock polymer solution in said mixture ofmethanol, acetic acid and water.
 9. The method of claim 2, wherein thestep of synthesizing includes the step of drying said[NOR]_(m)/[NORCOOH]_(n) diblock copolymer solution under vacuum.
 10. Themethod of claim 1, wherein the step of introducing includes the stepsof: dissolving said [NOR]_(m)/[NORCOOH]_(n) diblock copolymer intetrahydrofuran (THF) to form a diblock copolymer solution; and,introducing said FeCl₃ and CoCl₂ precursors into said diblock copolymersolution to form a resulting solution comprising:[NOR]_(m)/[NORCOOH]_(n):FeCl₃:CoCl₂ related each to the other inquantities of 1:25.0:12.5 mole.
 11. The method of claim 10, wherein thestep of introducing includes the step of forming solid films from saidresulting solution by static casting of said resulting solution.
 12. Themethod of claim 11, further wherein the step of introducing includes thestep of static casting of said resulting solution over a period of 72hours.
 13. The method of claim 11, wherein the step of processingincludes the step of washing said formed solid films with NaOH and waterto substitute chlorine atoms of said FeCl₃ and CoCl₂ molecules withoxygen atoms to form a plurality of nanoclusters of CoFe₂O₄ within said[NOR]_(m)/[NORCOOH]_(n) diblock copolymer.
 14. A method of roomtemperature synthesis of magnetic metal oxide nanoclusters within amatrix of a diblock copolymer, comprising the steps of: a. synthesizing,by a ring opening metathesis polymerization technique, said diblockcopolymer including a first polymer block and a second polymer blockhaving a predetermined repeat unit ratio m/n of said first and secondpolymer blocks; b. introducing, at room temperature, at least oneprecursor containing an at least one metal into one of said first andsecond polymer blocks, thereby forming in a liquid phase the diblockcopolymer containing said at least one metal, dissolving CoCl₂ intetrahydrofuran (THF) thus forming a solution of CoCl₂ in THF, anddissolving Lithium-trans-2,3-bis (Tert-butylamidomethyl) norborn-5-ene(Li₂(bTAN) in ether, thus forming a solution of Li₂ (bTAN) in ether, andadding said solution of Li₂ (bTAN) in ether to said solution of CoCl₂ inTHF to form cobalt (trans-2,3-bis(tert-butyl amidomethyl) norborn-5-ene(Co(bTAN)); and, c. processing said diblock copolymer containing said atleast one metal by a wet chemical technique to form a plurality of metaloxide nanoclusters within said diblock copolymer matrix, wherein saidmetal precursor is introduced prior to a microphase separation of thepolymer blocks.
 15. The method of claim 14, wherein the step ofsynthesizing includes the step of synthesizing said diblock copolymer[NOR]_(m)/[NOR-Co]_(n) by the ring opening metathesis polymerization ofnorbornene (NOR) and Co(bTAN) formed in said step (b), said firstpolymer block including norbornene (NOR) and said second polymer blockincluding Co(bTAN).
 16. The method of claim 15, wherein said m/n=500/40to form the [NOR]₅₀₀/[CO(bTAN)]₄₀ diblock copolymer.
 17. The method ofclaim 14, wherein the step of synthesizing the steps of: forming saidsolution of CoCl₂ in THF by dissolving 0.47 g (3.6 mmol) of said CoCl₂in 50 ml of said THF at the temperature −40° C.; forming said solutionof Li₂ (bTAN) in ether by dissolving 1 g (3.6 mmol) of said Li₂ (bTAN)in said ether; maintaining a mixture of said solution of CoCl₂ in THFand of said solution of Li₂ (bTAN) in ether at room temperature forapproximately 2 hours; and extracting said Co(bTAN) with 50 ml ofpentane.
 18. The method of claim 15, wherein the step of synthesizingincludes the step of preparing a 4% solution of norbornene (NOR) inbenzene by dissolving of 0.25 grams of norbornene (2.65⁻³ mol, 500equivalent) in 6 ml of benzene prior to said synthesis of said[NOR]_(m)/[NOR-CO]_(m).
 19. The method of claim 18, wherein the step ofsynthesizing includes the step of initiating the polymerization of said[NOR]_(m)/[Co(bTAN)]_(n) diblock copolymer by adding a Bis(tricyclohexylphosphine) benzylidine ruthenium (IV) dichloride catalystsolution to said solution of norbornene (NOR) in benzene to form an NORpolymer solution.
 20. The method of claim 19, wherein the step ofsynthesizing includes the step of adding 2.7 mg (5.3⁻⁶ mol, 1/500equivalent) of said catalyst solution.
 21. The method of claim 19,wherein the step of synthesizing includes the step of adding 5.45⁻² g ofsaid Co(bTAN) (21.4⁻³ mol, 40 equivalent) to said NOR polymer solutionafter approximately 15 minutes from the introduction of said catalystsolution to form a resultant said [NOR]_(m)/[Co(bTAN)]_(n) diblockcopolymer.
 22. The method of claim 21, wherein the step of synthesizingincludes the steps of: precipitating said resultant[NOR]_(m)/[Co(bTAN)]_(n) diblock copolymer in pentane; and, drying saidprecipitated [NOR]_(m)/[Co(bTAN)]_(n) diblock polymer.
 23. The method ofclaim 22, wherein the step of synthesis includes the steps of: preparinga 1% solution of said precipitated [NOR]_(m)/[Co(bTAN)]_(n) diblockcopolymer in benzene; forming solid films of said[NOR]_(m)/[Co(bTAN)]_(n) diblock copolymer by static casting of saidsolution of said precipitated [NOR]_(m)/[Co(bTAN)]_(n) diblock copolymerin benzene over a period of approximately 240 hours; and, washing saidsolid films with hydrogen peroxide (H₂O₂) for a period of approximately24 hours to form Co₃O₄ nanoparticles within [NOR]_(m)/[Co(bTAN)]_(n)diblock copolymer.
 24. A method of room temperature synthesis of CoFe₂O₄nanoclusters within a diblock copolymer matrix, comprising the steps of:ring opening metathesis polymerization of norbornene (NOR) andnorbornene trimethylsilane (NORCOOTMS) in presence of a catalyst to forma [NOR]₄₀₀/[NORCOOTMS]₅₀ diblock polymer; converting said[NOR]₄₀₀/[NORCOOTMS]₅₀ diblock polymer into a [NOR]₄₀₀/[NORCOOH]₅₀diblock copolymer by precipitating said [NOR]₄₀₀/[NORCOOTMS]₅₀ diblockpolymer in a mixture of methanol, acetic acid and water; introducingFeCl₃ and CoCl₂ precursors into said [NOR]₄₀₀/[NORCOOH]₅₀ diblockcopolymer, thus forming a mixture of said [NOR]₄₀₀/[NORCOOH]₅₀, FeCl₃and CoCl₂, the FeCl₃ and CoCl₂ molecules attaching themselves to theNORCOOH blocks of said [NOR]₄₀₀/[NORCOOH]₅₀ diblock copolymer; formingsolid films of said mixture of [NOR]₄₀₀/[NORCOOH]₅₀, FeCl₃ and CoCl₂;and, washing said solid films with NaOH and water, thus forming CoFe₂O₄nanoclusters within the [NOR]₄₀₀/[NORCOOH]₅₀ diblock copolymer matrix.25. The method of claim 24, wherein the step of ring opening metathesispolymerization includes the step of initiating formation of said[NOR]₄₀₀/[NORCOOTMS]₅₀ diblock polymer by adding said catalyst to said(NORCOOTMS) to create a poly-NORCOOTMS block, and further adding said(NOR) to said poly-NORCOOTMS block.
 26. The method of claim 24, furtherwherein the step of ring opening metathesis polymerization includes thestep of initiating formation of said [NOR]₄₀₀/[NORCOOTMS]₅₀ diblockpolymer by adding said catalyst to said (NOR) to create a poly-NORblock, and further adding said (NORCOOTMS) to said poly-NOR block.
 27. Amethod of room temperature synthesis of Co₃O₄ nanoclusters within adiblock copolymer matrix, comprising the steps of: a. synthesizingcobalt (trans-2,3-bis(tert-butylamidomethyl) norborn-5-ene(Co(bTan)) bymixing a solution of CoCl₂ in tetrahydrofuran and a solution ofLithium-trans-2,3-bis(tert-butylamidomethyl) norborn-5-ene (Li₂(bTAN))in ether; b. ring opening metathesis polymerization of norbornene (NOR)and said Co(bTAN) in the presence of a catalyst to form a[NOR]₅₀₀/[Co(bTAN)]₄₀ diblock copolymer; c. forming a plurality of solidfilms of said [NOR]₅₀₀/[Co(bTAN)]₄₀ diblock copolymer; and, d. washingsaid solid films with hydrogen peroxide (H₂O₂), thus forming a pluralityof Co₃O₄ nanoclusters within a matrix of the [NOR]₅₀₀/[Co(bTAN)]₄₀diblock copolymer.